Simplify temporary file handling in tests

Use delete=True (default) for NamedTemporaryFile instead of manually
managing cleanup with try/finally blocks. Keep file open during test
and let context manager handle automatic deletion. Also remove now-
unused os import.

Author: gpshead

Lib/test/test_multiprocessing_forkserver/test_preload.py

@@ -2,7 +2,6 @@
 
 import multiprocessing
 import multiprocessing.forkserver
-import os
 import tempfile
 import unittest
 from multiprocessing.forkserver import _handle_preload
@@ -124,54 +123,38 @@ class TestHandlePreload(unittest.TestCase):
 
     def test_handle_preload_main_on_error_fail(self):
         """Test that __main__ import failures raise with on_error='fail'."""
-        with tempfile.NamedTemporaryFile(mode='w', suffix='.py', delete=False) as f:
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.py') as f:
             f.write('raise RuntimeError("test error in __main__")\n')
-            bad_main_path = f.name
-
-        try:
+            f.flush()
             with self.assertRaises(RuntimeError) as cm:
-                _handle_preload(['__main__'], main_path=bad_main_path, on_error='fail')
+                _handle_preload(['__main__'], main_path=f.name, on_error='fail')
             self.assertIn("test error in __main__", str(cm.exception))
-        finally:
-            os.unlink(bad_main_path)
 
     def test_handle_preload_main_on_error_warn(self):
         """Test that __main__ import failures warn with on_error='warn'."""
-        with tempfile.NamedTemporaryFile(mode='w', suffix='.py', delete=False) as f:
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.py') as f:
             f.write('raise ImportError("test import error")\n')
-            bad_main_path = f.name
-
-        try:
+            f.flush()
             with self.assertWarns(ImportWarning) as cm:
-                _handle_preload(['__main__'], main_path=bad_main_path, on_error='warn')
+                _handle_preload(['__main__'], main_path=f.name, on_error='warn')
             self.assertIn("Failed to preload __main__", str(cm.warning))
             self.assertIn("test import error", str(cm.warning))
-        finally:
-            os.unlink(bad_main_path)
 
     def test_handle_preload_main_on_error_ignore(self):
         """Test that __main__ import failures are ignored with on_error='ignore'."""
-        with tempfile.NamedTemporaryFile(mode='w', suffix='.py', delete=False) as f:
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.py') as f:
             f.write('raise ImportError("test import error")\n')
-            bad_main_path = f.name
-
-        try:
+            f.flush()
             # Should not raise
-            _handle_preload(['__main__'], main_path=bad_main_path, on_error='ignore')
-        finally:
-            os.unlink(bad_main_path)
+            _handle_preload(['__main__'], main_path=f.name, on_error='ignore')
 
     def test_handle_preload_main_valid(self):
         """Test that valid __main__ preload works."""
-        with tempfile.NamedTemporaryFile(mode='w', suffix='.py', delete=False) as f:
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.py') as f:
             f.write('test_var = 42\n')
-            valid_main_path = f.name
-
-        try:
-            _handle_preload(['__main__'], main_path=valid_main_path, on_error='fail')
+            f.flush()
+            _handle_preload(['__main__'], main_path=f.name, on_error='fail')
             # Should complete without raising
-        finally:
-            os.unlink(valid_main_path)
 
     def test_handle_preload_module_on_error_fail(self):
         """Test that module import failures raise with on_error='fail'."""
@@ -191,15 +174,11 @@ def test_handle_preload_module_on_error_ignore(self):
 
     def test_handle_preload_combined(self):
         """Test preloading both __main__ and modules."""
-        with tempfile.NamedTemporaryFile(mode='w', suffix='.py', delete=False) as f:
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.py') as f:
             f.write('import sys\n')
-            valid_main_path = f.name
-
-        try:
-            _handle_preload(['__main__', 'os', 'sys'], main_path=valid_main_path, on_error='fail')
+            f.flush()
+            _handle_preload(['__main__', 'os', 'sys'], main_path=f.name, on_error='fail')
             # Should complete without raising
-        finally:
-            os.unlink(valid_main_path)
 
 
 if __name__ == '__main__':